Likewise, the invention relates to arrangements and improvements in drill rigs, generally comprising a derrick and a power source for rectilinear displacement of a working head or the like to and fro, e.g. a working head for connection of a drill string having a bit. Thus, the invention aims at utilizing such a prior art drill rig and assigns thereto extra equipment enabling the above-mentioned hauling, possibly insertion, of objects into the ground.
NO patent application No. 952813 deals with a method of piling in connection with drilled vertical or substantially vertical bore holes for receiving casings of the kind desired to be hauled up again and reused when the piling is finished. The present invention is not restricted to hauling up casings extending vertically in a driven down position, the invention also being associated with ashore drilling generally, and comprises hauling up casings in connection with deviation drilling.
As mentioned, NO patent application No. 952813 deals with a method of piling in connection to a preceding drilling operation carried out by means of a combined drilling/piling rig, and wherein, by means of a drilling means included as a working tool at the end of a drill string in a drilling rig, a vertical hole is drilled, and the piling can start from the bottom of this bore hole. A casing of the kind to be hauled up in accordance with the present invention, is releasably suspended from said drilling means by means of a reamer ring which, together with the casing, surrounds the bit, leaving a radial clearance, so that the casing is left standing on the lower end thereof at the bottom of the bore hole when the drill string is pulled up after terminated drilling.
When the piling is finished, it is desirable to have the casing hauled up for reuse. In accordance with the present invention, such casings are intended to be hauled up in an efficient way by means of a rational method, wherein the hauling device shares power source with the drilling machine in that respect that hauling device and drilling machine may use the same power source for reciprocating, rectilinear displacement movements. Downward insertion of drill string and hauling the same up are, thus, carried out through a common power source; this is also the case when lowering the catcher means of the hauling device in order to bring the former to grip and surround the upper end of the casing, and also upon hauling the same up, possibly followed by lowering the same into position. On the other hand, the rotation of the drill string/bit is based on the use of a separate power source, e.g. a hydraulic turning motor. In prior art technique, a separate rig or simlar machine has to be used for hauling up the casing.
From NO patent application No. 952813 it is previously known to dispose the drilling machine pivotally about a vertical axis at one vertical side of the drilling machine. Thus, the drilling machine may be swung laterally out of the vertical path from the upper end of the derrick down to the bottom of a predrilled hole. Such a pivotal capability is required in piling. Also, it is used a pipe narrower than the casing but surrounding the drill string. The annulus between said narrower pipe and the casing is made so narrow as possible in order to make more efficient the transport and removal of cuttings and to reduce the requirement for the air compressor's capacity. Said narrower pipe is brought to follow the drill string up and out of the bore hole, the casing--as mentioned--being left behind standing on the bore hole bottom.